Body weight patterns from 20 to 49 years of age and subsequent risk for diabetes mellitus - The Johns Hopkins precursors study

Background: Obesity in middle age is a well-known risk factor for the devel opment of type 2 diabetes mellitus. However, the importance of weight and w eight gain at younger ages is less certain. Objective To determine the relationship of body weight patterns from 20 to 49 years of age with the subsequent risk for type 2 diabetes mellitus. Setting: An ongoing longitudinal study of former medical students. Particip ants: Nine hundred sixteen white men without diabetes at 50 years of age. Measurements: Weight and height measured in medical school, then assessed b y mailed questionnaire to 49 years of age. Main Outcome: Incident type 2 diabetes mellitus based on physician self-rep ort. Results: During 14 255 person-years of follow-up, there were 35 incident ca ses of type 2 diabetes mellitus (2.5 per 1000 person-years). After simultan eous adjustment for age, physical activity, lifetime maternal history of di abetes, and smoking, body mass indexes (BMIs; calculated as weight in kilog rams divided by the square of height in meters) at 25, 35, and 45 years of age were all strongly associated with diabetes risk (relative risks for ove rweight [BMI greater than or equal to 25.0] vs not overweight, >3.0; all Ps <.05), as were maximum and average BMI to 49 years of age. The relationship of BMI at 25 years of age to diabetes risk was substantially attenuated by adjustment for BMI at 45 years of age and average BMI, but was Independent of weight change, weight variability, or maximum BMI. Conclusion: In men, overweight at 25 years of age strongly predicts diabete s risk in middle age, largely through its association with overweight at 45 years of age and high average BMI to 49 years of age.